A substrate in which a high-dielectric-constant gate insulator is formed on a silicon substrate with an interface layer film sandwiched in between is housed in a chamber. A mixed gas of ammonia and nitrogen gas is supplied to the chamber to form an ammonia atmosphere, and flash light is applied in the ammonia atmosphere from flash lamps to the surface of the substrate for an emission time of 0.2 milliseconds to one second. This allows the high-dielectric-constant gate insulator to be heated in the ammonia atmosphere and accelerates nitriding of the high-dielectric-constant gate insulator. Since the time for which flash light is applied is an extremely short time, nitrogen will not reach and nitride the interface layer film, which is formed as a base of the high-dielectric-constant gate insulator.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A heat treatment method for heating a substrate in which a high dielectric constant film is deposited on a base material with an interface layer film sandwiched in between, the method comprising the steps of: (a) housing said substrate in a chamber; (b) supplying ammonia to said chamber to form an ammonia atmosphere, while pressure in said chamber is reduced to less than atmospheric pressure; and (c) applying flash light to a surface of said substrate housed in said chamber to heat said high dielectric constant film.
2. The heat treatment method according to claim 1 , wherein the flash light applied in said step (c) has a spectral distribution that has a peak in a wavelength range of 200 to 300 nm.
3. The heat treatment method according to claim 1 , wherein the flash light applied in said step (c) has a spectral distribution showing that relative intensity at a wavelength of 300 nm is 20% or more higher than an intensity at a wavelength of 500 nm.
4. The heat treatment method according to claim 1 , wherein said high dielectric constant film is heated in an ammonia atmosphere in said step (c) to accelerate nitriding of said high dielectric constant film.
5. The heat treatment method according to claim 1 , wherein a time for which flash light is applied in said step (c) is 0.2 milliseconds or more and one second or less.
6. The heat treatment method according to claim 1 , wherein said high dielectric constant film is annealed prior to said step (c).
7. The heat treatment method according to claim 1 , wherein said high dielectric constant film is annealed after said step (c).
8. A heat treatment apparatus for heating a substrate in which a high dielectric constant film is deposited on a base material with an interface layer film sandwiched in between, the apparatus comprising: a chamber in which said substrate is housed; an atmosphere forming part that supplies ammonia to said chamber to form an ammonia atmosphere, while pressure in said chamber is reduced to less than atmospheric pressure; and a flash lamp that applies flash light to a surface of said substrate housed in said chamber.
9. The heat treatment apparatus according to claim 8 , wherein said flash lamp emits flash light with a spectral distribution that has a peak in a wavelength range of 200 to 300 nm.
10. The heat treatment apparatus according to claim 8 , wherein said flash lamp emits flash light with a spectral distribution showing that relative intensity at a wavelength of 300 nm is 20% or more higher than an intensity at a wavelength of 500 nm.
11. The heat treatment apparatus according to claim 8 , wherein a time for which said flash lamp emits flash light is 0.2 milliseconds or more and one second or less.
12. The heat treatment apparatus according to claim 8 , wherein said chamber has a window made of synthetic quartz, the window passing through the flash light emitted from said flash lamp.
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December 21, 2015
January 31, 2017
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